Optical phonons in millerite (NiS) from single‐crystal polarized Raman spectroscopy

Guillaume, François; Huang, Shanshan; Harris, Kenneth David Maclean; Couzi, M.; Talaga, David

doi:10.1002/jrs.2014

Cited by 36 publications

(20 citation statements)

References 9 publications

(9 reference statements)

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“…The Raman spectrum of LDHS and LDHGOS can be seen from Figure S4a (Supporting Information). The peaks located at wavenumber of 286.6 and 339.4 cm −1 can be ascribed to Mn 3 O 4 , while the peaks at 540.3 and 1057.6 cm −1 are caused by NiS . From the Raman spectrum, it is deduced that sulfidation can effectively increase the conductivity of GO, simultaneously remove the defects, and also dope S into the graphitic structure, which will be elucidated later.…”

Section: Resultsmentioning

confidence: 88%

Sulfidation of NiMn‐Layered Double Hydroxides/Graphene Oxide Composites toward Supercapacitor Electrodes with Enhanced Performance

Chen

Wang

et al. 2015

Advanced Energy Materials

260

142

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Supercapacitors can deliver high‐power density and long cycle stability, but the limited energy density due to poor electronic and ionic conductivity of the supercapacitor electrode has been a bottleneck in many applications. A strategy to prepare microflower‐like NiMn‐layered double hydroxides (LDH) with sulfidation is delineated to reduce the charge transfer resistance of supercapacitor electrode and realize faster reversible redox reactions with notably enhanced specific capacitance. The incorporation of graphite oxide (GO) in NiMn LDH during sulfidation leads to simultaneous reduction of GO with enhanced conductivity, lessened defects, and doping of S into the graphitic structure. Cycling stability of the sulfidized composite electrode is enhanced due to the alleviation of phase transformation during electrochemical cycling test. As a result, this sulfidation product of LDH/GO (or LDHGOS) can reach a high‐specific capacitance of 2246.63 F g−1 at a current density of 1 A g−1, and a capacitance of 1670.83 F g−1 is retained at a high‐current density of 10 A g−1, exhibiting an outstanding capacitance and rate performance. The cycling retention of the LDHGOS electrode is also extended to ≈ 67% after 1500 cycles compared to only ≈44% of the pristine NiMn LDH.

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Section: Resultsmentioning

confidence: 88%

Sulfidation of NiMn‐Layered Double Hydroxides/Graphene Oxide Composites toward Supercapacitor Electrodes with Enhanced Performance

Chen

Wang

et al. 2015

Advanced Energy Materials

260

142

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“…In addition, it is important to note that small peaks are present, corresponding to NiS 2 (ref. 44 ) (276, 447 and 465 cm −1 ) and NiS (379 cm −1 ) 45 . The Raman spectroscopy results combined with the EDS and ICP-OES elemental analysis establish that the main electrodeposition product is Ni 3 S 2 .…”

Section: Resultsmentioning

confidence: 92%

A porous proton-relaying metal-organic framework material that accelerates electrochemical hydrogen evolution

et al. 2015

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The availability of efficient hydrogen evolution reaction (HER) catalysts is of high importance for solar fuel technologies aimed at reducing future carbon emissions. Even though Pt electrodes are excellent HER electrocatalysts, commercialization of large-scale hydrogen production technology requires finding an equally efficient, low-cost, earth-abundant alternative. Here, high porosity, metal-organic framework (MOF) films have been used as scaffolds for the deposition of a Ni-S electrocatalyst. Compared with an MOF-free Ni-S, the resulting hybrid materials exhibit significantly enhanced performance for HER from aqueous acid, decreasing the kinetic overpotential by more than 200 mV at a benchmark current density of 10 mA cm−2. Although the initial aim was to improve electrocatalytic activity by greatly boosting the active area of the Ni-S catalyst, the performance enhancements instead were found to arise primarily from the ability of the proton-conductive MOF to favourably modify the immediate chemical environment of the sulfide-based catalyst.

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“…The Ni x S y /CNT nanocomposite shows seven Raman signals at 146, 246, 297, 348, 371, 1352, and 1587 cm –1 ; the first five signals are characteristic of Ni x S y nanoparticles, whereas the last two signals can be attributed to the C=C bonds of the CNTs. The first five signals are the E, A 1 , A 1 , E, and A 1 modes of the Ni x S y nanoparticles, respectively , . The first five signals do not shift, and the intensities of these signals decrease after the formation of the Ni x S y /CNT nanocomposite.…”

Section: Resultsmentioning

confidence: 96%

Enhanced Hydrogen Evolution Catalysis at the Liquid/Liquid Interface by Ni_xS_y and Ni_xS_y/Carbon Nanotube Catalysts

2017

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NixSy (NiS and Ni17S18) nanoparticles and their nanocomposite with carbon nanotubes (NixSy/CNT) were synthesized by a modified hydrothermal method and characterized by X‐ray diffraction, Raman spectroscopy, scanning electron microscopy, and energy‐dispersive X‐ray microanalysis. The synthesized materials were used as hydrogen evolution catalysts at the water/1,2‐dichloroethane interface by using decamethylferrocene as a lipophilic electron donor. The hydrogen evolution reaction in biphasic systems was investigated by two‐phase reactions and by cyclic voltammetry with a four‐electrode system. A kinetic study of the hydrogen production was also performed. The rates of the reactions catalyzed by the NixSy nanoparticles and the NixSy/CNT nanocomposite were found to be about 690‐fold and 2000‐fold higher, respectively, than the rate for the reaction performed in the absence of a catalyst.

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Optical phonons in millerite (NiS) from single‐crystal polarized Raman spectroscopy

Cited by 36 publications

References 9 publications

Sulfidation of NiMn‐Layered Double Hydroxides/Graphene Oxide Composites toward Supercapacitor Electrodes with Enhanced Performance

Sulfidation of NiMn‐Layered Double Hydroxides/Graphene Oxide Composites toward Supercapacitor Electrodes with Enhanced Performance

A porous proton-relaying metal-organic framework material that accelerates electrochemical hydrogen evolution

Enhanced Hydrogen Evolution Catalysis at the Liquid/Liquid Interface by Ni_xS_y and Ni_xS_y/Carbon Nanotube Catalysts

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Optical phonons in millerite (NiS) from single‐crystal polarized Raman spectroscopy

Cited by 36 publications

References 9 publications

Sulfidation of NiMn‐Layered Double Hydroxides/Graphene Oxide Composites toward Supercapacitor Electrodes with Enhanced Performance

Sulfidation of NiMn‐Layered Double Hydroxides/Graphene Oxide Composites toward Supercapacitor Electrodes with Enhanced Performance

A porous proton-relaying metal-organic framework material that accelerates electrochemical hydrogen evolution

Enhanced Hydrogen Evolution Catalysis at the Liquid/Liquid Interface by NixSy and NixSy/Carbon Nanotube Catalysts

Contact Info

Product

Resources

About

Enhanced Hydrogen Evolution Catalysis at the Liquid/Liquid Interface by Ni_xS_y and Ni_xS_y/Carbon Nanotube Catalysts